FFS, yfz450. Really? This is going to be a great MX quad with yfz450 shocks and spacers.
Don't buy the boost bottle, it will just be anther reason your quad doesn't finish the race.
You don't need skid plates for MX.
Ditch the T5 pipes for something that is more MX friendly such as PT mids.
A steering damper will be helpful, especially with those wheel spacers adding tons of bump steer.